Lithospermic acid, the active principle of a variety of herbal preparations prepared from Lithospermum ruderale and Lithospermum officinale has been shown to inhibit the in vivo and in vitro activity of TSH, LH, FSH, oxytocin, and glucagon but not insulin or ACTH. Preliminary pharmacological findings show promise in the treatment of diabetes, hyperthyroidism, and in fertility control. A biosynthetically modeled total synthesis of this important compound is proposed, providing hitherto unobtainable supplies of the pure lithospermic acid. Possibilities for the preparation of active analogues are discussed.